Ruby on Rails
Cartographer Plugin

Allows you to plop Google Maps down into your Rails app without knowing a lick of ECMAScript Javascript.

USAGE
@map = Map.new(:name => 'mymap', :width => 300, 
               :center => Point.new(-110, 33))

svn: svn://rubyforge.org//var/svn/cartographer/trunk/vendor/plugins/cartographer/

See also Plugins and the rubyforge page

FYI, I think this plugin was incorrectly refactored and may take a lot of finessing to get it running correctly (the docs are outdated as well). Also, it has not been up graded to support V2 of the Google Maps API.

Related
If you want to integrate (Google) maps in your Rails application be sure to also check YM4R.